In the normal process of supplying of fuel to internal combustion engines, as in carbureted gasoline engines, fuel is supplied by a fuel pump directly to the carburetor float bowl. The flow of fuel into the float bowl is typically controlled by a needle valve in the fuel inlet line, the needle valve being connected to a float in the bowl.
The ease of drawing fuel from the float bowl into the chamber where it is mixed with air for subsequent feed to the cylinders is variably dependent on the level of fuel in the float bowl. The higher the fuel level, the more easily it is drawn into the mixing chamber for a given air flow, and thus the greater the quantity of fuel used. Ideally, of course, the quantity of fuel used should be the minimum amount which will support proper operation of the engine. Greater amounts are wasted. Lesser amounts cause poor performance.
The level of fuel in the float bowl depends, in combination, on the setting of the float and the pressure exerted on the needle valve by the fuel coming from the fuel pump. At any time, the fuel level in the float bowl may be changed by adjusting the float setting. Thus is there direct control of the float setting. In conventional fuel systems, however, the pressure exerted on the needle valve remains a variable. The source of the variability is in the fuel pump, in that, as the fuel pump wears with use, the outlet pressure from the pump to the needle valve gradually declines. Typical outlet pressure from a new fuel pump is in the range of 10 to 15 pounds per square inch (psi). As the pump wears, the pressure gradually drops until it reaches zero which is usually associated with pump failure. Since, in normal consumer operation, the fuel pump may go its entire useful life without inspection or evaluation, and likewise, the carburetor float may never be adjusted, the float level may be set for satisfactory operation of the engine at minimum fuel pressure output from the fuel pump, even when the engine is fairly new. This assures satisfactory engine power output at any fuel pump pressure. Given this setting of the float level, and the higher fuel pump outlet pressure of a newer pump, the fuel level in the float bowl is higher than necessary when the pump output pressure is in the higher portion of its overall lifetime range. Given the fact that the fuel level in the float bowl is higher than necessary during this period, the amount of fuel drawn into the chamber where it is mixed with air is also greater than necessary; and this extra fuel is, on the whole, wasted. As the fuel pump wears, of course, and the fuel pressure to the needle valve drops, the amount of fuel wasted in this way decreases, as the fuel level in the float bowl declines somewhat in response to the drop in fuel pressure at the needle valve. This normal change in the fuel pressure with wear on the fuel pump, in many cases, as described, results in a more economical utilization of fuel toward the latter stages of the useful life of the fuel pump. Earlier in the life of the fuel pump, fuel is typically wasted, as above.
It is thus an object of this invention to provide a means of supplying a constant fuel pressure at the needle valve inlet to a carburetor, on an engine, so that the fuel level in the float bowl will remain constant.
It is another object to provide a pressure regulator in the fuel line which will supply fuel to the carburetor at a constant pressure.
It is yet another object to provide a fuel supply system which can provide a constant pressure of fuel to the carburetor.
In another sense, it is an object to provide a method of supplying fuel to an engine at a constant pressure.
Indeed, it is yet another object to provide a kit which may be used to modify a fuel supply system such that the modified fuel supply system will supply fuel to the engine at a constant pressure.